Fixed my boost issue.....but spun a bearing this morning

[donniekak]

You know the holes in the rod bearings aren't their oil feeds right? The oil is fed through the crank, the rod bearings could have no holes at all and not starve the bearing.
The mains look hammered from detonation, or running timing past mbt. This causes a localized low pressure situation in the rods, and the rest is history. The bearing with the chunk out of it in particular is a classic sign of detonation overloading a bearing.

[J. Fast]

You know the holes in the rod bearings aren't their oil feeds right? The oil is fed through the crank, the rod bearings could have no holes at all and not starve the bearing.
The mains look hammered from detonation, or running timing past mbt. This causes a localized low pressure situation in the rods, and the rest is history. The bearing with the chunk out of it in particular is a classic sign of detonation overloading a bearing.

There's no tangs left on the bearings. They aren't egg shaped. One main was fatigued... the other ate it's failing friend. There's no light going thru this bearing...



The big chunks broken loose that you are describing are from the rod banging on the crank from the above oil starved bearing that lost its clearance and sent the slack back to the main.

Bi-Metal bearing is too soft of bearing for this application. It needed a tri-metal bearing. Bi-Metal pretty much only work on cast cranks because they polish. If you try and put a bi-metal bearing over a once tri-metal bearing it will spin in a very short period of time.

Lastly, there is no sign of detonation in the combustion chambers.

[J. Fast]

I will say I do agree with you Don, to an extent regarding oil cavitation or bearing overloading being an accompanying root cause. Similar damage can be caused by detonation, aeration, or oil cavitation. Any of those conditions will blast the plating right off the steel bearing backing too. An overload such as detonation has similar tells that point to bearing fatigue or eccentric collapse, especially after being smacked repeatedly beyond it's design limit.

Detonation overload failure due to pressure spikes will indeed blast off the plating like depicted in one pic. It's the other observations that when put all together tell the whole story. For some reason I'm thinking you've seen a lot of blown engines. That can be good and bad

[Hans@GZP]

That's a 2 bolt turbo block.

That piece you found in your oil pan is from one of your valve covers. You used too long of a bolt on one of your timing belt covers is my guess. Pull the valve covers and look inside where all of the bolts for the timing covers are. You will find a chunk missing.

[Erron Spalsbury]

Here's my best swag at it. It looks to me like oil starvation. That one bearing though, that is missing parts, that's a weird one. I've seen many, many spun bearings and the only time I've seen chuncks like that remove it was because of pre-ignition or way too much timing WITH oil starvation. I'm assuming that's the bottom bearing, what does the top one look like?

Sin, just curious, what rpm do you take the motor to when you're drag racing? What's the max advance on the car?

[familyMAN]

Oil starvation keeps being mentioned. I am not sure how that would arise after so many successful miles. Clearances must not have been too tight from initial build correct? Not sarcasm...what would cause the "oil starvation" on this engine?

[Erron Spalsbury]

It's actually a pretty common danger in todays high RPM tuning scenario. There's two scenarios at play here for a brief discussion, oil starvation and oil in suspension. Oil starvation is typically by cavitation or low oil level. Low oil level doesn't mean that someone forgot to check the oil but rather one of the other two before mentioned. In suspension means that you've pumped all of the oil out of the oil pan up into the motor and gravity hasn't brought enough back down for the pump to pick up yet. This is why you see -10 AN lines on the back of high RPM 4 bangers, to get the oil back to the pan quicker than the tiny oil galleys in the head allow for. The other portion of this is the oil return galley that is controlled by the oil pressure regulator piston and spring. Was it's capacity to return the oil back to the pan exceeded? Could be I suppose...

The thrust surface you mentioned Jer, that's totally normal for a drag car even though it looks like the beginning stages of crank walk. Pull up to the line, push in clutch (which has the lowest oil pressure possible, typically idle) then rev the shit out of the car before launching. This is the fatal flaw of any pivot/ball clutch setup, the immense amount of lateral torque that is put on the crank. Add that along side with "clutch must be depressed to start the car" and it's a recipe for failure, no question. This is why I run a HTOB and a twin. The lateral forces are exponentially smaller.

[Greg E]

Oil starvation keeps being mentioned. I am not sure how that would arise after so many successful miles. Clearances must not have been too tight from initial build correct? Not sarcasm...what would cause the "oil starvation" on this engine?

The oil starvation comes from debris from bearing damage and excessive tolerances caused by crank flex. Crank flex is caused from excessive cylinder pressure which is usually the result of knock or too much timing with too much boost.

Basically, denial that the tune was too agreasive is the issue here.

[Greg E]

It's also been my observation that misfires damage the engine too. Be it from riding the rev limiter or fuel cut for an extended period of time, some how this seems to ruin engines as well. Don't yet have an explsination for this.

[familyMAN]

It's actually a pretty common danger in todays high RPM tuning scenario. There's two scenarios at play here for a brief discussion, oil starvation and oil in suspension. Oil starvation is typically by cavitation or low oil level. Low oil level doesn't mean that someone forgot to check the oil but rather one of the other two before mentioned. In suspension means that you've pumped all of the oil out of the oil pan up into the motor and gravity hasn't brought enough back down for the pump to pick up yet. This is why you see -10 AN lines on the back of high RPM 4 bangers, to get the oil back to the pan quicker than the tiny oil galleys in the head allow for. The other portion of this is the oil return galley that is controlled by the oil pressure regulator piston and spring. Was it's capacity to return the oil back to the pan exceeded? Could be I suppose...

Have never heard of suspension or drainback being an issue on a 3S. Maybe you guys have it with sustained high rpm road racing (I believe sin only drag races though) or possibly too much crankcase pressure not allowing drainback??

The oil starvation comes from debris from bearing damage and excessive tolerances caused by crank flex. Crank flex is caused from excessive cylinder pressure which is usually the result of knock or too much timing with too much boost.

Basically, denial that the tune was too agreasive is the issue here.

That I do understand. Seemed like he was playing with fire on a tune that he didn't understand (banging against fuel-cut) and making changes without full understanding. Still haven't seen a log or map posted.